Question 1

A beam of light in air enters a glass slab with an index of refraction of 1.40 at an angle of incidence of 30.0°. What is the angle of refraction?

Accepted Answer

A)  20.9° 
B)  47.5° 
C)  51.8° 
D)  30.0° 
E)  14.9°

Question 2

A certain slide projector has a lens of focal length 15.0 cm. This lens forms an image measuring 100 cm × 100 cm on the screen when a slide whose dimensions are 50.0 mm × 50.0 mm is being magnified. How far from the lens should the screen be placed?

Accepted Answer

The answer of A certain slide projector has a lens...

Question 3

A beam of light traveling in air strikes a glass slab at an angle of incidence less than 90°. After entering the glass slab, what does the beam of light do? (There could be more than one correct choice.)
A) I follows the same path as before it struck the glass.
B) It follows the normal to the glass slab.
C) It bends away from the normal at the point of contact.
D) It bends closer to the normal at the point of contact.
E) It slows down.

Accepted Answer

The answer of A beam of light traveling in air...

Question 4

Two thin lenses, one a converging lens and the other a diverging lens, are separated by 1.00 m along the same principal axis, as shown in the figure. The magnitude of the focal length of the converging lens is 25 cm, while the magnitude of the focal length of the diverging lens is 40 cm. An object 8.25 cm tall is placed 35 cm to the left of the converging lens.
(a) Where is the final image produced by this combination of lenses? (Give your answer relative to the diverging lens.)
(b) Compared to the object, is the final image upright or inverted? Is it real or virtual?

Accepted Answer

The answer of Two thin lenses, one a converging lens...

Question 5

A light ray in glass arrives at the glass-water interface an an angle of θ = 48° with the normal. The refracted ray in water makes an angle φ = 72° angle with the normal, as shown in the figure.The index of refraction of water is 1.33. The angle of incidence is now changed to θ = 37°. What is the new angle of refraction φ in the water?

Accepted Answer

A)  50° 
B)  48° 
C)  46° 
D)  52° 
E)  54°

Question 6

An oil layer that is 5.0 cm thick is spread smoothly and evenly over the surface of water on a windless day. A light ray from the air above enters the oil at 45° with the normal and then goes into the water. What is the angle of refraction of this ray in the water? The index of refraction for the oil is 1.15, and for water it is 1.33.

Accepted Answer

A)  27° 
B)  32° 
C)  36° 
D)  39°

Question 7

The focal length of a convex mirror is has a magnitude of 20 cm. What is its radius of curvature?

Accepted Answer

A)  -10 cm 
B)  40 cm 
C)  -40 cm 
D)  -20 cm 
E)  20 cm

Question 8

A 4.0-cm tall object is placed 60 cm in front of a converging lens of focal length of magnitude 30 cm. What are the nature and location of the image?

Accepted Answer

A)  The image is real, 2.5 cm tall, 30 cm on the same side as object. 
B)  The image is virtual, 2.5 cm tall, 30 cm on the other side of the lens. 
C)  The image is virtual, 2.0 cm tall, 15 cm on the other side of the lens. 
D)  The image is virtual, 4.0 cm tall, 60 cm on the same side as object. 
E)  The image is real, 4.0 cm tall, 60 cm on the other side of the lens.

Question 9

A seed is 15 mm in front of a converging lens, and the image of the seed is 4.0 mm behind the lens. What is the focal length of the lens?

Accepted Answer

A)  11 mm 
B)  5.5 mm 
C)  3.8 mm 
D)  3.2 mm

Question 10

Which of the following terms describe lenses that are thicker at the center than at the edges? (There could be more than one correct choice.)

Accepted Answer

A)  converging lenses 
B)  diverging lenses 
C)  concave lenses 
D)  convex lenses

Question 11

An object is placed near a concave mirror having a radius of curvature of magnitude 60 cm. How far should you place the object from the mirror so that the lateral magnification produced by the mirror will be +2.5?

Accepted Answer

A)  18 cm 
B)  24 cm 
C)  30 cm 
D)  36 cm 
E)  42 cm

Question 12

If a spherical convex mirror has a radius of curvature R, the magnitude of its focal length is

Accepted Answer

A)  R/2. 
B)  R/4. 
C)  R. 
D)  2R. 
E)  4R.

Question 13

An object is placed 50 cm in front of a concave mirror with a focal length of 25 cm. What is the magnification produced by the mirror?

Accepted Answer

A)  -0.50 
B)  -1.0 
C)  +1.5 
D)  -2.0 
E)  +1.0

Question 14

Light in a transparent material that has an index of refraction of 1.333 strikes the boundary with another transparent material for which the index of refraction is 1.010. What is the critical angle for total internal reflection between these two materials?

Accepted Answer

The answer of Light in a transparent material that has...

Question 15

A thick slab of plastic lies at the bottom of a tank filled with water having an index of refraction of 1.33. A narrow laser beam is shone directly downward through the water on the plastic. You then gradually rotate the laser, thereby increasing the angle with respect to the normal that it strikes the plastic. You carefully note that at the instant the beam makes an angle of 66.5° with the normal in the water, no light enters the plastic, but it did enter for angles smaller than that. What is the speed of light in the plastic slab? (c = 3.00 × 10⁸ m/s)

Accepted Answer

The answer of A thick slab of plastic lies at...

Question 16

If you stand in front of a convex mirror, at the same distance from it as its focal length,

Accepted Answer

A)  you won't see your image because there is none. 
B)  you won't see your image because it is focused at infinity. 
C)  you will see your image and you will appear smaller than you. 
D)  you will see your image and you will appear larger than you. 
E)  you will see your image and it will be the same size as you except upside down.

Question 17

A beam of light, traveling in air, strikes a plate of transparent material at an angle of incidence of 56.0°. It is observed that the reflected and refracted beams form an angle of 90.0°. What is the index of refraction of this material?

Accepted Answer

A)  1.40 
B)  1.43 
C)  1.44 
D)  1.48

Question 18

A convex mirror has a focal length of magnitude f. An object is placed in front of this mirror at a point $\frac { 2 } { 3 }$ f from the face of the mirror. The image will appear

Accepted Answer

A)  behind the mirror. 
B)  upright and reduced. 
C)  upright and enlarged. 
D)  inverted and reduced. 
E)  inverted and enlarged.

Question 19

An object is placed 15 cm to the left of a double-convex lens of focal length 20 cm. Where is the image of this object located?

Accepted Answer

A)  60 cm to the right of the lens 
B)  60 cm to the left of the lens 
C)  8.6 cm to the right of the lens 
D)  8.6 cm to the left of the lens 
E)  30 cm to the left of the lens

Question 20

A thin lens projects an image of a man as shown in the figure. Rays marked A, B, and C travel to the lens from the man's ear. Draw the paths of these three rays after they have passed through the lens. Note that A is parallel to the principal axis, B goes through the center of the lens, C goes through the focal point on the left, and the point marked f is the focal point on the right of the lens.

Accepted Answer

The answer of A thin lens projects an image of...

Exam 18: Ray Optics